Software Development Life Cycle

What are the parties involved in system testing?

2009-10-31T07:19:00.000-07:00

What are the parties involved in system testing?

Project Manager on Co-ordination
Members of the Project Team on the actual testing
Project Coordinator on the execution of the tests
Users on involvement and feedback

What are some of the other system test items?

2009-10-31T07:18:00.000-07:00

What are some of the other system test items?

Conversion Testing
Installation Testing
Hardware Configuration Testing
Performance Testing
Recovery Testing
Security Testing
Runability Testing
Usability Testing

How is software released to system test?

2009-10-31T07:16:00.000-07:00

How is software released to system test?

Builds or loads
controlling changes
Quality of software released

What test data and tools are available?

2009-10-31T07:15:00.000-07:00

What test data and tools are available?

Existing test sets and files
Simulators
Capture/Playback tools

What are the Goals of System Test?

2009-09-20T03:54:00.001-07:00

The goals of system test include:

Breaking the system
Demonstrating readiness for use
Understanding performance limits
Test user procedures

Criteria of a System Test

2009-09-20T03:53:00.001-07:00

Criteria of a System Test includes:

Compliance with Functional Requirements
Performance at all Interfaces
Performance at Boundaries and under stress
Adequacy of user documentations

What is System Testing?

2009-09-20T03:51:00.000-07:00

System Testing:

Measures compliance with system objectives
Tests functional requirements and system requirements
Uses system test environment setup by testing team

The Trend in Integration Test

2009-09-17T18:12:00.000-07:00

The trend in Integration Test:

traditional top-down or bottom-up approaches favour the developers
the functional approach favours the testers
the object-oriented approach naturally leads the developers into functional integration

Advantages and Disadvantages of Functional Integration

2009-09-17T18:10:00.001-07:00

Advantage:

Accomplishes system function

Disadvantages:

May be hard to define data to test lower level module conditions
May be hard to locate faults

What is Functional Integration?

2009-09-17T18:09:00.000-07:00

Functional Integration:

Start with a specific function
Use incomplete components, stubs and drivers as needed to conduct testing
Progress to multiple functions
Functional cases may be usable for system testing

Disadvantages of Bottom-Up Integration

2009-09-13T06:10:00.000-07:00

Disadvantages of Bottom-Up Integration includes:

Cases may not be usable at the system level
May be hard to detect interface faults
major design faults will be detected late

Advantages of Bottom-Up Integration

2009-09-13T06:09:00.000-07:00

Advantages of Bottom-Up Integration includes:

Easy to locate faults
Does not need stubs

What is Bottom-Up Integration?

2009-09-05T20:18:00.000-07:00

Bottom-Up Integration is:

Driver is built to quality software modules
Modules are linked when a driver can be replaced by a new module and all modules called by the new module have been qualified

Disadvantages of Top-Down Integration

2009-09-05T20:16:00.000-07:00

Disadvantages of Top-Down Integration includes:

May be hard to define and input data to test lower level module conditions
Lower level modules are not tested as frequently as upper level modules
Functionality may be severely limited or smart stubs required

Advantages of Top-Down Integration

2009-09-05T20:15:00.000-07:00

Advantages of Top-Down Integration includes:

Accomplishes "working" system
Easy to locate faults
Does not need drivers

What is Top-Down Integration?

2009-09-05T07:08:00.000-07:00

Top-Down Integration is:

Start with control modules
Add a few modules for each build
Data injected from "qualified" modules
Missing modules simulated with stubs

Supporting Software in Integration Test

2009-09-05T07:05:00.000-07:00

Some supporting software in Integration Test include:

Drivers
Programs that invoke the software being tested and simulate the activity of higher level application components. They usually provide test input and report test result.
Stubs
Dummy program modules used to enable the testing of higher-level invoking components. Their functional capabilities range from none to extensive simulations of actual application modules.

Key Integration Issues in SDLC

2008-05-04T07:37:00.000-07:00

What modules should be assembled and tested as a group?

Functional subassemblies
Top level grouping working down
Bottom level groupings work up
Crtical feature first

How much scaffolding cde or test support code is required?

How much testing is appropriate?

Subassembly
Interfaces only
All invoking functions and features
Stress and break conditions

How will problems be isolated?

Integration Test Criteria

2008-05-01T07:13:00.000-07:00

Integration Test Criteria includes:

Compliance with Sub-Assumbly Functional Requirements
Assessment of Timing, Sizing and Accuracy
Performance at Boundaries and Under Stress
Measurement of Functional Test Coverage
Measurement of Software Reliability

Objective of Integration Testing

2008-05-01T07:10:00.001-07:00

The objective of Integration Test is to ensure that various system parts of related components and programs work properly together.

It includes:

Integrates Components.
Components with Components Tests
Hardware Interfaces Tests
External Software Interfaces Tests
Functional Requirements Tests
Sub-Assembly Tests

Program Debugging

2008-05-01T07:08:00.000-07:00

There are 3 different approaches to debugging and they includes:

Induction Approach
Deduction Approach
Intuition Approach

Difficulties in Program Walkthrough

2008-03-07T18:30:00.000-08:00

As testing should be done by someone else, some difficulties of a Program Walkthrough includes:

cannot depend on human eyes
Programmers would be reluctant
difficulties in inviting external party
resources

Structural Testing in SDLC

2008-03-07T18:23:00.000-08:00

Continuing on the Structural Testing:

More powerful form of test is Path Coverage
This strategy ensures that all statements in the program are executed at least once and conditional statements are tested for both true and false cases
The starting point is to derive a program flow graph
A flow graph consists of nodes representing decisions and edges showing flow of control
Tester must not be seduced into thinking that such testing is adequate
Cyclomatic complexity is a measure of the program's control complexity. The data complexity is not taken into account
Program fragments which are equivalent in function may not have the same cyclomatic complexities
It is generally true that the # of paths through a program is proportional to its size. Thus, as modules are integrated into systems, it is unfeasible to use structural testing techniques.

What is Structural Testing

2008-02-22T19:53:00.000-08:00

Structural Testing includes:

Cover structure, quality and style.
Implementation based.
Best done by programmer.
Not aiming at testing functions or detecting missing functions.
The tester analyses the code and use knowledge about the structure of a component to derive the test data.
Simplest form of testing includes:
- Statement coverage
- Branch coverage

Cause-effect Analysis

2008-02-22T19:49:00.000-08:00

Another analysis you should consider in Functional Testing is Cause-effect Analysis. This includes:

Even when a program operates successfully for individual test inputs, combinations of these inputs may detect program errors.
Involves examining the output and analysing to see if combinations of input partitions always cause outputs in the same output partition to be producted.
The causes of these effects used as test cases.

Boundary Value Analysis

2008-02-22T19:43:00.000-08:00

In Functional Testing, one of the consideration is Boundary Value Analysis. This includes:

Input conditions are 'edges' of equivalence class.
Values like above and below range, minimum and maximum number and up to the array limit.

What is Equivanlence Testing

2008-01-12T06:31:00.000-08:00

Equivalence Testing is:

Input conditions are partitioned into Equivalence Classes.
Classes like specific numeric value, range of values and set of related values.

Example:

A database state that the product must be able to handle any no of records from 0 to 100,000.

Art of Testing in SDLC

2008-01-12T06:27:00.000-08:00

Art of testing is to set up a small, manageable set of test cases in such a way as to maximize the chances of detecting a fault while minimizing the chances of wasting a test case by having the same fault detected by more than one test case.

The technique use is Equivalence Testing + Boundary Vaule Analysis + Cost Effect Analysis

Functional Testing - SDLC

2008-01-07T06:48:00.000-08:00

What is Functional Testing?

It is function oriented.
Test cases prepared by looking at logic from outside just as though it was a black box.
Concentration on the verification process.

So what should be considered in this functional testing black box?

Under waht conditions would we not perform the test?
What should we know and need to know about the input and output?
What can we state about our assumptions and expectations?
How much must we know about the intended use of the system?
How important are the various attributes and how much can we trade one off again another?
What is the one factor against wich all others can be judged?

Module Testing

2008-01-07T06:28:00.000-08:00

For testing, there are 2 ways of systematically contructing test data to test a module. These include:

Functional Test
To test according to the specification.
Structural Test
Testing on the code.

Structured Walkthough Tips

2008-01-07T06:19:00.000-08:00

When conducting Structured Walkthough, I have the following tips:

Make sure that the team is ready.
Record preparation time and issues ready to be raised.
Take notes.
Summarize the work done page by page.
Record assumptions, questions and dissent.
Record minority views.
Record quality issues and their conflict with standards.
Take care over sudden agreement over correctness.
Summarize total effort.
Make sure that the team does not get bogged down in discussions or correction activities.
Focus on internal and external interfaces.
Make sure to review the final product instead of the person.

Conducting Structure Walkthrough in SDLC

2008-01-05T07:48:00.000-08:00

Structure Walkthrough can be conducted:

at any point in time during SDLC.
to review users requirements in the feasibility study stage or the external design stage, system design during the internal design stage or source coding duirng the development stage.

What is Structured Walkthrough

2008-01-05T07:43:00.000-08:00

Structured Walkthrough is:

a tool for analysing the design of a system to ensure it addresses all requirements.
a mean of ensuring conformity to standard.
a mean to make reviewees more conscious of the way the product looks.
used as a learning experience for the team.

Prototyping in SDLC

2008-01-05T07:36:00.000-08:00

A prototype is:

a demonstration system.
a partially or fully working system waiting for idea testing and modification to meet requirements.
an intermediate state that exhibits the essential features of a later generation.
technique for clarifying user requirements (especially on user interface).
can also verify the feasibility of a design.

Overview on External and Internal Design

2008-01-04T07:26:00.000-08:00

External Design

In this phase, the full details of the system functions, screen and report formats, external interfaces, security and audit controls, operational procedures, recovery and contingency procedures and reponse times are defined.

Internal Design

This phase is concerned with the internal details of the system such as databases/files, records and programs. For each program it defines the functions it performs, the files accessed and the input and/or outputs processed.

Overview of SDLC

2008-01-04T07:09:00.000-08:00

System Development Life Cycle (SDLC) sets out the steps to be performed when developing systems, the work to be done in each step and the deliverables to be produced. It applies to all types of system development projects. By following SDLC, it ensures planning the project at the beginning and monitoring it along the way so that the schedule is met and the final system meets the requirements.

SDLC comprises a number of consecutive phases:

Initial Request
Feasibility Study
External Design
Internal Design
Programming
System Test
Acceptance Test
Implementation
Post Implementation